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Welcome to the new "mystery magic lights" from Nitecore, the SENS series.

Following up on the recent launch of The Explorer Series, Nitecore is quick to release this new accelerometer-equipped series of lights. The SENS lights use the angle/tilt of the light to adjust output. I am sure you all have a lot of questions about how that works in practice, so here we go …

Manufacturer Specifications:

Common Specs:

LED: CREE XP-G R5

High efficiency circuit

3 brightness levels - Lo, Med, Hi – in regular brightness control

Continuously-variable output through active dimming system with auto-adjust control

UPDATE April 2014: The current manuals for the SENS AA and CR models no longer support 1x 3.7V Li-ion (i.e., 14500 or RCR are listed as "banned"). I don't know if Nitecore has actually changed anything in the circuit, but these Li-ion cells are no longer supported.

My SENS samples came without retail packaging – only a small split ring was included with each one. I do not know what retail packaging will look like. I received the SENS CR (1xCR123A/RCR), SENS Mini (1xCR2), and SENS AA (1xAA).

I will focus on the SENS CR here for the general build discussion, updating with additional pics from the other models when aspects differ.

In keeping with their twisty design, the SENS lights are fairly small for their respective classes. I will be providing detailed size and weight comparisons/pics in the detailed sections on each model – scroll down for details.

The SENS series looks a lot like the earlier EZ series of twisty lights from Nitecore – quite petite, with visible brass heatsinks. The SENS CR, Mini and AA all have the same diameter head, although the battery tube is bit narrower on the SENS AA. This differs slightly from the early EZ series lights, which had smaller heads on the CR2 and AA versions. Scroll down for the detailed comparison pics for their respective classes.

My samples have a matte black finish, with no obvious chips or damage on the bodies. There is knurling on the body tube and head, but I don't find it very aggressive – grip is OK, but could be better. Identification labels on the body are clear and bright against the black background.

Overall body wall thickness is on the thin-side, but the lights still feel solid (good weight in the hand with batteries installed). Screw threads are rather fine, as is common on twisty lights. I found the action slightly stiff, but can be improved with lube. There isn't that much play in the threads on my samples.

The SENS series lights use an optic to produce their beam (i.e., no reflector). The overall optic size and appearance is similar to the XP-E-equipped Fenix E11, as shown below. This should result in a decent hotspot/corona with minimal spill (i.e., output gradually fading away from the hotspot).

Fenix E11 on the left, SENS AA on the right

Scroll down for specific beamshots of each model, relative to its class counterparts.

And now, the most distinctive part – the user interface is based on a built-in accelerometer that can adjust output based on tilt angle.

User Interface

The SENS series lights are built around a traditional twisty interface – tighten for on, loosen for off. The lights come on in a graded way (i.e., quickly ramp up from dark to the light, rather just jump to specific levels).

The default "brightness control" mechanism is illustrated in this cartoon from Nitecore:

You get constant output at one of three defined levels (Lo, Med and Hi). You set the constant output mode by adjusting the original angle of the light at activation. That is, if a light is angled parallel to the ground (i.e., pointed straight ahead), the light come on in Hi. If you are partially angled down, the lights come on in Med. If you are pointed down to a greater degree (or straight down), the lights come on in Lo.

Critical to how this mode functions, the accelerometer sensor shuts off immediately after activation. So you can now wave the light around, and it remains locked in your pre-set output chosen at activation.

Basically, what is novel here is the means to select the Lo, Med, Hi – the actual levels remain constant during use, like all other lights. If you want to change the output level, you have to cycle the light off-on at a new initial angle to choose a different level.

The other option is the "active dimming technology" mode, where you can dynamically alter output in a continuously-variable way, based on the current angle of the light. In other words, the accelerometer sensor remains active during continuous use, constantly re-adjusting the output based on the current angle.

To activate this mode, turn the light on pointed straight up. As you lower the light, the output will drop in a continuously-variable way between parallel to the ground (Max) and perpendicular straight-down (Min).

Note there is a slight lag as the accelerometer sensor responds, and the change in output is gradual (especially when lowering the output). Just as when you turn the light on in the default "brightness control" mode, there is a graded response as the light changes modes during angling (i.e., no abrupt changes).

There are no strobe/SOS modes on the SENS series.

The Nitecore documentation is not very specific on what range of tilt angles produce the four possible outcomes upon activation (i.e., the three defined outputs or the continuously-variable option). To help you out, I have actually determined the relative angles using a protractor on my samples. Below is a graph of relative angle and output mode, using the same orientation as the earlier Nitecore cartoon (i.e., top of the image is up, far left or right is parallel to the ground).

The white area at the top of the graph is what produces the continuously-variable mode (i.e., anything higher a ~45 degree up-angle at activation will enter this mode). The constant Hi mode is produced by anything between a ~45 degree up-angle and a ~5 degree down-angle. The constant Med mode is produced by anything between a ~5 degree down-angle to a ~45 degree down-angle. The constant Lo mode is produced by anything greater than ~45 degree down-angle.

To make the above clearer in practice, please see my detailed examination of the build and user interface in my video overview:

Video was recorded in 720p, but YouTube typically defaults to 360p. Once the video is running, you can click on the configuration settings icon and select the higher 480p to 720p options. You can also run full-screen.

PWM/Strobe

There is no sign of PWM that I can see, at any output level – the lights appear to be current-controlled.

Due to twisty interface, there is no standby mode to worry about – the lights are not drawing any power when off.

Testing Method:

All my output numbers are relative for my home-made light box setup, a la Quickbeam's flashlightreviews.com method. You can directly compare all my relative output values from different reviews - i.e. an output value of "10" in one graph is the same as "10" in another. All runtimes are done under a cooling fan, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.

UPDATE April 2014: The current manuals for the SENS AA and CR models no longer support 1x 3.7V Li-ion (i.e., 14500 or RCR are listed as "banned"). I don't know if Nitecore has actually changed anything in the circuit, but these Li-ion cells are no longer supported.

All lights are on Turbo/Max on 1x AW protected RCR in the first set of panels, followed by 1xCR123A in the second. Lights are about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.

And now on primary 3V 1xCR123A:

As you can see, the optic on SENS CR is different from the more common reflector style. The SENS CR has fairly bright hotspot and corona, but with gradual drop-off of spill as you move away from it (i.e., a less defined spillbeam edge). This is common on lights with this sort of optic.

Throw/Output Summary Chart:

My summary tables are reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. Please see http://www.flashlightreviews.ca/FL1.htm for a discussion, and a description of all the terms used in these tables.

UPDATE April 2014: The current manuals for the SENS AA and CR models no longer support 1x 3.7V Li-ion (i.e., 14500 or RCR are listed as "banned"). I don't know if Nitecore has actually changed anything in the circuit, but these Li-ion cells are no longer supported.

My summary tables are reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. Please see http://www.flashlightreviews.ca/FL1.htm for a discussion, and a description of all the terms used in these tables.

All lights are on Max output on Sanyo Eneloop AA NiMH. Lights are about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.

Throw/Output Summary Chart:

My summary tables are reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. Please see http://www.flashlightreviews.ca/FL1.htm for a discussion, and a description of all the terms used in these tables.

UPDATE April 2014: The current manuals for the SENS AA and CR models no longer support 1x 3.7V Li-ion (i.e., 14500 or RCR are listed as "banned"). I don't know if Nitecore has actually changed anything in the circuit, but these Li-ion cells are no longer supported.

Output/Runtime Comparison:

UPDATE March 2014: according to the current SENS AA product sheet, 3.7V Li-ion 14500 are no longer supported. I have left the 14500 runtimes above up for historical comparison for the original SENS release.

---------

General Output Comments:

Please refer back to the individual light reviews above for detailed tables comparing output and throw for each light, relative to its respective class.

One general conclusion that I can draw is that the reported peak beam intensity and distance measures seem accurate, for all lights, for the identified battery type.

To better allow you to compare output at all levels on all lights, below are detailed tables for each model, on all supported battery types. I have indicated the manufacturer's specs for the identified cell type.

Note that Min refers to absolute lowest light level available in continuously-variable mode. The Max output in this mode was always the same as the Hi level in the regular brightness control mode.

UPDATE March 2014: according to the current SENS AA product sheet, 3.7V Li-ion 14500 are no longer supported. I have left the 14500 column above up for historical comparison for the original SENS release.

Again, in general terms, Nitecore seems to be pretty accurate in their relative output lumen reporting, just as I observed for most of the Explorer series lights.

As you would expect, output levels are higher across the board on 1x 3.7V Li-ion sources. Although relative levels are maintained, there is little difference between Med and Hi.

General Runtime Comments:

Note that I haven't tried to test the continuously variable levels (as I would have to mount both my lightbox and light at an angle). So my comments below refer the "regular brightness control" Lo/Med/Hi pre-set levels.

On the pre-set output levels, the SENS lights are all well-regulated on all primary battery sources, at all levels tested (i.e. very flat stabilization typically). 1x3.7V Li-ion regulation is typically less stable, at least initially.

Output/runtime efficiency seems very good relative to the XP-G R5 class – about what you would expect for good current-controlled lights. One stand-out here is the SENS Mini, which seems to be exceptionally efficient for the class (but I have few lights to compare to).

My results are also very close to the report ANSI FL-1 reported runtimes for each light (note that the ANSI FL-1 standard is time to 10% initial output).

It's nice to see all the output, throw and runtime specs are pretty accurate for these lights.

Potential Issues for the SENS series

Thread action can be a bit stiff, and the lights may be hard to use single-handed (depending on the size of your hands).

While I like the gradual ramp up or down in brightness, the lights can be a bit slow to respond in ramping down in the continuously-variable mode (while comparatively quick in ramping up).

It takes some getting used to the continuously-variable adjustment based on tilt angle, but this happens faster than you might expect. In any case, there is always the regular brightness-control mode (i.e., three defined levels, with accelerometer turned off after activation).

I don't know what final packaging will include, but there doesn't seem to be any easy way to secure a pocket clip to these lights.

My SENS AA has to be tightened fairly tightly to activate. Twisty lights always have the potential to be battery crushers, so you should periodically check your cells.

My SENS CR has battery rattle when not fully tightened and in use.

UPDATE April 2014: according to the current SENS AA and CR product sheets, 3.7V Li-ion 14500/RCR are no longer supported.

Preliminary Observations

The SENS series is definitely unique – I haven't reviewed an accelerometer-based control interface before.

Build-wise, the series is actually fairly similar to the earlier Nitecore EZ series – except for the more consistent head size, and the use of an optic instead of a reflector. Fans of the familiar twisty interface (and tiny overall size that it allows) will find a lot that looks familiar here.

But the user interface is definitely terra nova. Like most here, I was skeptical initially of how this sort of interface could work in practice. The short answer is that is does, but it requires some practice.

Nitecore was wise to provide two options to control the light – both methods have their advantages and disadvantages.

Let's start with the continuously-variable output (i.e., activate the light pointed up, for continual sensor control). I was surprised at how quickly I could get use to using the light this way. If it dimmed or increased in brightness too much upon angling, a slight angle change restored the desired level of output. It is kind of like how you adjust how you point a constant-output light – to control the amount light falling on your target, you can move between the bright hotspot and the dimmer spill. It is much the same here – angle-control quickly becomes part of your innate handling regimen, and you aren't even consciously-aware you are doing it.

The one thing missing in this mode is the ability to "lock" the light at a given level temporarily. This would be especially helpful for when you wanted to look down but maintain a higher brightness (e.g., going down stairs, looking down over an edge, etc.). I am generally a fan of visually-linear control rings for this reason – I can dynamic dial the light up or down, and it stays put once I stop turning the ring. Perhaps some sort of front-mounted clicky control could work well with this technology (e.g., half-press to hold a level, or use a half-press to activate the sensor, etc.).

Of course, you have the alternate option – the "regular brightness control" – where you start the light in one of three initial output states and it stays "locked" for the duration of the on-cycle. While this is a useful option, I would still like to have the flexibility of taking advantage of both features simultaneously (i.e., a variable lock, without having to turn off and re-position).

I am not sure why there are only three levels available in the regular brightness control mode (i.e., as opposed to a continuously variable range of initial activations). But the relative efficiency of the three levels is excellent, well in keeping with other good current-control lights at these levels.

Originally, I thought I would use this regular brightness control mode the most, but I found it a bit inconvenient given the small size of the lights (and my rather long fingers). Except for the 1xAA version, I typically needed to use two hands to activate the lights (i.e., I can't easily grip both the body and twist the head one-handed on the CR or Mini, while still accurately pointing at my target during activation). And having to hold the light two-handed defeats the whole purpose of a tilt-sensor – I need to artificially hold the light at a specific angle to get the output I want. This is just a personal problem I find with small twisties in my hands.

Another option for Nitecore to consider is bundling the sensor with a clicky interface. A typical single tailcap clicky may be problematic, as that would require an overhand tactical grip during activation (which is probably more likely to produce a down-angle than under-hand carry). So I can see why they went with this twisty option in the SENS series. Maybe a dual switch design, where a tailcap clicky turns the light on, and a front-mounted switch controls whether the accelerometer is active? That could give you the temporary "lock" option I would like to see.

I do like the functionality the accelerometer-control interface provides. It is a novel approach, and one that worked consistently in my testing. You quicky adapt to using this novel interface. I think it would be interesting to see it implemented in other physical builds and control mechanisms – especially in a larger set of lights that fit more comfortably in my hands for single-handed use.

UPDATE April 2014: The current manuals for the SENS AA and CR models no longer support 1x 3.7V Li-ion (i.e., 14500 or RCR are listed as "banned"). I don't know if Nitecore has actually changed anything in the circuit, but these Li-ion cells are no longer supported.

Yes, a good point - the XL100 pioneered an accelerometer-based UI. But I understand how it was applied was different from here (I have not handled a XL100 personally).

Originally Posted by GordoJones88

Can you test how well the Active Dimming Technology works when flapping your arms up and down in the air like a chicken. A video would be great. Thanks.

No need - the answer is clear: the lights would stay on at full brightness the whole time.

Anything higher than a 5% down angle is full brightness (i.e. the top half of your swing would be Max). And the lights are slow to ramp down in the Active Dimming Technology mode. So if you swing your arms fast enough, the light would stay in Hi through the whole arc.

Originally Posted by Norm

Another fantastic selfbuilt review, if I had any criticism at all, is that a contrasting background would make the video easier to watch.

Yes, the background is not ideal - but that's because it is the corner of my working desk (the same location I use for all my detailed light pics). I have a simple setup with my camera phone on a stand - not very high tech, I'm afraid.

I have just adjusted the brightness and constrast through YouTube, should help with visibility. It may take a few mins before the processing is finished and the adjusted video shows up.

First of all, thank you SelfBuilt for composing such a very in-depth review about this new series of flashlights!

While reading this review, I couldn't help but notice in this picture:

That the spring used at the bottom of the battery tube seems to be of the "leaf spring" type. Now, I've always had the impression that "coil springs" were sturdier and more reliable than the older leaf springs. Thus, I would like to know if there's any reason for NiteCore to use a leaf spring in this particular set up. Also, I would like to know if this leaf spring is easy to replace by the layman user in case one of the leaves of said spring was to break or flatten down--conversely, is this leaf spring available for purchase as a spare part?

Eventually, is there any reason why this series of flashlights, and particularily the AA model, do not have a pocket clip? In my limited experience, that's the most useful accessory that can be fitted to a carry-in-the-pocket flashlight.

That the spring used at the bottom of the battery tube seems to be of the "leaf spring" type. Now, I've always had the impression that "coil springs" were sturdier and more reliable than the older leaf springs. Thus, I would like to know if there's any reason for NiteCore to use a leaf spring in this particular set up. Also, I would like to know if this leaf spring is easy to replace by the layman user in case one of the leaves of said spring was to break or flatten down--conversely, is this leaf spring available for purchase as a spare part?

I would have to leave that to Nitecore to explain, but if I were to hazard a guess, I suspect it has to do with the twisty mechanism.

There is enough tension provided by screwing down the head that a tailcap spring is not actually required in this case. Note that a lot of twisty lights with a high number of fine head screw threads (as in the case here) actually only have a small raised post in the tail (e.g. the EZ lights, a number AAA-style lights, etc). For this reason, twisty lights all have the potential to be battery crushers.

I am just guessing, but I suspect the "leaf spring" design here is to provide some flexible give (i.e. to reduce the risk of negative battery terminal denting, which I have seen with post-style tails). I always recommend that users keep an eye on the both terminal ends of their battery, though (e.g., I've seen the positive terminals get bent down as well in twisty lights).

is there any reason why this series of flashlights, and particularily the AA model, do not have a pocket clip? In my limited experience, that's the most useful accessory that can be fitted to a carry-in-the-pocket flashlight.

Good question ... I don't know what Nitecore is bundling with the lights, but there doesn't seem to be a lot place to secure a clip on these models.

I am just guessing, but I suspect the "leaf spring" design here is to provide some flexible give (i.e. to reduce the risk of negative battery terminal denting, which I have seen with post-style tails). I always recommend that users keep an eye on the both terminal ends of their battery, though (e.g., I've seen the positive terminals get bent down as well in twisty lights).

Couldn't have they used a coil spring instead of a leaf spring for this application? The advantage that I can see using a coil spring is that it'll hardly ever break or flatten (if designed properly). The only twisty flashlight that I can think of the top of my head using a coil spring is the EagleTac D25A Mini.

Also, I can think of a couple of disadvantages of using a coil spring. Firstly, I'm "almost sure" that a coil spring is going to take more vertical space than a leaf spring and, secondly, a fully compressed coil spring will most probably act like a "post-style tail".

Also, I can think of a couple of disadvantages of using a coil spring. Firstly, I'm "almost sure" that a coil spring is going to take more vertical space than a leaf spring and, secondly, a fully compressed coil spring will most probably act like a "post-style tail".

Yes, I would say those are both likely true statements. I guess we will have to wait and see how well the leaf springs hold up in use.

A conical coil spring will take up no more vertical space than a leaf spring, because the coils will nest inside each other as the spring compresses. Furthermore, because a comparably-sized coil spring is made of a relatively long piece of wire, the torsion on each segment of wire is much lower than the flexion on the relatively short leaves of the leaf spring.

I doubt the leaf spring will reach its stress-cycle limit quickly, but a coil spring would last effectively forever, which would extend the life of the light until the electronics fail, which is how electro-mechanical devices like flashlights *should* work. They probably used a leaf spring just to save money, because they can be stamped with a cutting die from a sheet of metal.

I doubt the leaf spring will reach its stress-cycle limit quickly, but a coil spring would last effectively forever, which would extend the life of the light until the electronics fail, which is how electro-mechanical devices like flashlights *should* work. They probably used a leaf spring just to save money, because they can be stamped with a cutting die from a sheet of metal.

There's a set of these lights reviewed on the "Layman's Flashlight Reviews" website where one of the leaf springs effectively flattened. Apparently, that particular light continued to work well, despite the battery rattling around when the light was switched off. That sounds like a premature failure to me!

Otherwise, I fully agree that electro-mechanical devices should last until the electronics fail (and if said electronics were user replaceable that'd be awesome!).

I got my Nitecore Sens CR123 version and I found a couple issues. I'm not sure if this one is defective or they are all like this but when using a regular CR123 everything seems fine. However with a RCR123 (AW brand black label) if you start out turning it on straight up it does not seem to dim when pointing it down. Even straight down it seemed to be full brightness or almost (I haven't put a light meter on it yet but if it dims it isn't much). However if I start out and turn it on straight down it is obviously at a lower level by far. I waited at least 10 seconds for it to drop down from the straight up start on position and that brings up the other issue. It gets too hot to hold the head within about 5 to 10 seconds at most when on the RCR123. I just now tried this again and I think I can see it ramping down just a little when pointing straight down. Also interesting to note how it starts out very dim when turned on straight down and ramps up to the low setting while still pointing straight down. To bad they didn't keep low a little lower IMO. Trippy light however it doesn't seem to like RCR123's too much and without them it's not that bright. I'd give it 6 out of 10 stars (would only be 4 or 5 if it wasn't for the uniqueness of the acclerometer).

There is no important work, there are only a series of moments to demonstrate your mastery and impeccability. Quote from Almine

I'm not sure if this one is defective or they are all like this but when using a regular CR123 everything seems fine. However with a RCR123 (AW brand black label) if you start out turning it on straight up it does not seem to dim when pointing it down.

Awesome review as usual. I might have to pick one of these up to play with. I just bought an EZ CR2 as I had a munch of CR2 cells to burn through. The SENS Mini does look pretty cool. Too bad it lacks the threaded part for screwing on to a tri-pod though. It would be cool if the head would interchange with the Nitecore EZ CR2 body...

Hmmm, are your batteries hot off the charger? I have been testing with cells that have typically been run for a few secs to a minute or two. No issue with any of them.

It wasn't off the charger but fairly new and read 4.18V. I tried with an older batt, 4.16V, and same thing. When I started in the low position both batteries showed quite a bit lower than when using the swing down method.

It wasn't off the charger but fairly new and read 4.18V. I tried with an older batt, 4.16V, and same thing. When I started in the low position both batteries showed quite a bit lower than when using the swing down method.

Hmm, disconcerting. That's probably around the same voltages as my cells - and Min output is definitely lower than the defined Lo mode in my case.

Looks like Nake is having the same issue. I've run down my RCR123 to about 3.85 volts and it's still doing the same thing as far as not dimming down compared to starting on low. I've given it way longer than 7 seconds but no dimming level compared to starting it on low. However I take back what I said about it not being that bright on a CR123. It's not quite as bright but still very bright. One other thing I've noted now is how really very bright this light is on the RCR123. It looks brighter on high than the new Sunwayman M11R I just got when it's on high. Sunwayman is supposed to be 230 Lumens on high. Nitecore is supposed to be 190 on high. Either the Sunwayman is weak or this Nitecore is extra bright. It's been compared ceiling bounce and about 15 feet away on a white wall. I'll take some Lux readings if I get a chance.

There is no important work, there are only a series of moments to demonstrate your mastery and impeccability. Quote from Almine

One other thing I've noted now is how really very bright this light is on the RCR123. It looks brighter on high than the new Sunwayman M11R I just got when it's on high. Sunwayman is supposed to be 230 Lumens on high. Nitecore is supposed to be 190 on high. Either the Sunwayman is weak or this Nitecore is extra bright.

The rated ANSI specs for lights refer to 1xCR123A, and are fairly accurate in my testing on my samples (i.e., I estimate 230 for M11R and 210 for the SENS CR).

With RCR, results can vary greatly, depending on how the circuit handles it. In this case, output increases on both lights on RCR, but more so for the SENS CR (as you will see in my tables in the review, I estimate 320 lumens for M11R, 370 lumens for SENS CR).

Again, that can be highly variable among different lights. My Sunwayman V11R is also ~220 lumens on 1xCR123A, but a whopping ~550 lumens (initially) on RCR. So max performance on CR123A is never really an indicator of what to expect on RCR.

Anyway, sorry to hear about the lack of dimming issue on yours and Nake's samples. Definitely doesn't seem right.

My two AA samples landed Friday from Light Junction. I am very pleased. I have only used them around the house so far, but I have to say that my initial impression that I would mostly use the fixed modes was correct. My problem with the ADT is that it gets too bright too soon for indoor use. I have to deliberately point it near straight down to keep it at a reasonable brightness.

That said, they are as great as I thought for being able to select any one of the three modes directly, no cycling required. I had a bit of a time getting medium every time until I realized that I need to hold it closer to horizontal. Trying for 45 degrees puts it right on the edge of grabbing low, and you won't get high until you are within about 10 degrees of horizontal. I also notice that compared to other twisties, it requires more rotation to get in and out of positive "on" and "off" respectively. I need to use more than a quarter turn going each way for positive activation.

The optic beam was a pleasant surprise, a large hotspot with some gradual spill that never has a hard edge to it. The only thing more I could ask for in the beam would be a neutral tint, but as cools go, this one is very free of annoying tints.

Mode spacing is very good, and I really can't imagine having a brighter low, it is the mode I use most. That is why I only got the AA models.

I also agree with selfbuilt that the ADT is too slow to dim when lowering the light, although I don't think that would explain most of what keeps me from using it about the house. Additionally, I am not as fond of the soft start as I thought I would be, because it is slow enough that I am never quite sure when I have twisted the light enough for low or medium activation, as I have to wait a second or two to see if it is coming on or not. I don't want to just twist it until it gets real firm, as that could over compress the flat spring, and cause the type of issues many are concerned about. But I am getting better with practice at gauging the amount of twist I need for reliable turn-on. It's just different from all of my other twisties with hard stops.

Another big thanks to selfbuilt for the review, as it looks like it helped me make a very good choice on these lights!